Currently it seems that last.fm scrobbling on the Android client is actually handled by the server app, which seems a little needlessly complex. Why not have the Android player implement SLS and scrobble directly from my phone?
http://code.google.com/p/a-simple-lastfm-scrobbler/
(I'm not involved in that project, my current problem with Android scrobbling is far from my first and I'd just like to see something more reliable.)